Slow release compound fertilizer via phosphoric acid passivation of magnesium slag

Abstract

The invention relates to the field of preparation of slow release compound fertilizers, in particular to a method for preparing a slow release compound fertilizer via phosphoric acid passivation of magnesium slag. The method, which is simple in production technology, low in cost, environmentally friendly, and high in slow release effect, comprises the following steps: a, preparation of a raw material: grinding magnesium slag, urea and industrial potassium sulfate respectively into powder, and preparing a phosphoric acid solution; b, mixing the prepared phosphoric acid solution with powder of magnesium slag, and stirring, so as to generate a calcium phosphate magnesium salt cementitious inorganic binding agent, and passivate the powder of magnesium slag; c, respectively adding powder of urea and that of industrial potassium sulfate into magnesium phosphate slag reactant obtained after a passivation reaction, and carrying out mixing granulation. The method is mainly applied to resource utilization of magnesium slag.

Description

technical field

[0001] The invention relates to the field of preparation of slow-release compound fertilizers, in particular to a method for preparing slow-release compound fertilizers through phosphoric acid passivation of magnesium slag. Background technique

[0002] Magnesium slag is a by-product in the process of producing primary magnesium. In my country, 95% of primary magnesium is produced by the Pidgeon method. Every time a magnesium metal enterprise produces 1 ton of crude magnesium, it will produce 6~10 tons of magnesium slag at the same time. With the rapid development of my country's magnesium smelting industry, the discharge of magnesium slag is increasing day by day, and the stockpiling of a large amount of magnesium slag will cause a series of environmental problems. In recent years, the resource utilization of magnesium slag is mainly concentrated in the fields of building materials, coal desulfurization, modifiers, etc., and there are problems such as few u...

Examples

Embodiment 1

[0030] Weigh a certain amount of magnesium slag, urea, and industrial potassium sulfate and use a small grinder to grind them through an 80-mesh sieve for use, absorb 11.00mL of 85% phosphoric acid and add 5mL of water to dilute for use. Weigh 20g of magnesium slag powder passed through a 80-mesh sieve and put it into a beaker, pour the diluted phosphoric acid into the beaker, stir quickly with a glass rod to make the magnesium slag and phosphoric acid mix evenly and fully react, then add urea powder passed through an 80-mesh sieve 41.04g and 27.20g of industrial potassium sulfate powder, mix well, add 8mL water, mix and granulate in a disc granulator. Then it is taken out and dried to obtain the magnesium slag-based slow-release fertilizer. The slow-release performance of the magnesium slag-based slow-release fertilizer was measured by the water-soluble method, and the initial release rate of potassium was 2.60%, and the cumulative release rate in 28 days was 65.69%, which me...

Embodiment 2

[0032]Suck and weigh a certain amount of magnesium slag, urea, and industrial potassium sulfate and use a small grinder to grind them through an 80-mesh sieve for use. Take 11.00mL of 85% phosphoric acid and add 5mL of water to dilute for use. Weigh 20g of magnesium slag powder passed through a 80-mesh sieve and put it into a beaker, pour the diluted phosphoric acid into the beaker, stir quickly with a glass rod to mix the magnesium slag and phosphoric acid evenly, and then add 41.04g of urea powder passed through an 80-mesh sieve and 27.20g of industrial potassium sulfate powder, mix well and add 8mL of water, mix and granulate in a disc granulator, then put the granules into a small coating machine, add 7g of cement, roll for a certain period of time, and use The constant temperature heater blows and dries the fertilizer. After the drying is completed, the binder (self-made organic binder) is sprayed into the coating machine, and then 8g of cement is added, and it is rotated ...

Embodiment 3

[0034] Weigh a certain amount of magnesium slag, urea, and industrial potassium sulfate and use a small grinder to grind them through an 80-mesh sieve for use, absorb 8.75mL of 85% phosphoric acid and add 5mL of water to dilute for use. Weigh 20g of magnesium slag powder passed through a 80-mesh sieve and put it into a beaker, pour the diluted phosphoric acid into the beaker, stir quickly with a glass rod to mix the magnesium slag and phosphoric acid evenly, and then add 41.04g of urea powder passed through an 80-mesh sieve and industrial potassium sulfate powder 27.20g, mix well, add 8mL water, and granulate in a disc granulator. After granulation, put it into a small coating machine, add 7g of magnesium slag, and after rolling for a certain period of time, use a constant temperature heater to blow dry the fertilizer. After drying, spray a binder (self-made organic binder) into the coating machine, and then Add 8g of magnesium slag, rotate for a certain period of time, and th...

technical field

[0001] The invention relates to the field of preparation of slow-release compound fertilizers, in particular to a method for preparing slow-release compound fertilizers through phosphoric acid passivation of magnesium slag. Background technique

[0002] Magnesium slag is a by-product in the process of producing primary magnesium. In my country, 95% of primary magnesium is produced by the Pidgeon method. Every time a magnesium metal enterprise produces 1 ton of crude magnesium, it will produce 6~10 tons of magnesium slag at the same time. With the rapid development of my country's magnesium smelting industry, the discharge of magnesium slag is increasing day by day, and the stockpiling of a large amount of magnesium slag will cause a series of environmental problems. In recent years, the resource utilization of magnesium slag is mainly concentrated in the fields of building materials, coal desulfurization, modifiers, etc., and there are problems such as few u...

Examples

Embodiment 1

[0030] Weigh a certain amount of magnesium slag, urea, and industrial potassium sulfate and use a small grinder to grind them through an 80-mesh sieve for use, absorb 11.00mL of 85% phosphoric acid and add 5mL of water to dilute for use. Weigh 20g of magnesium slag powder passed through a 80-mesh sieve and put it into a beaker, pour the diluted phosphoric acid into the beaker, stir quickly with a glass rod to make the magnesium slag and phosphoric acid mix evenly and fully react, then add urea powder passed through an 80-mesh sieve 41.04g and 27.20g of industrial potassium sulfate powder, mix well, add 8mL water, mix and granulate in a disc granulator. Then it is taken out and dried to obtain the magnesium slag-based slow-release fertilizer. The slow-release performance of the magnesium slag-based slow-release fertilizer was measured by the water-soluble method, and the initial release rate of potassium was 2.60%, and the cumulative release rate in 28 days was 65.69%, which me...

Embodiment 2

[0032]Suck and weigh a certain amount of magnesium slag, urea, and industrial potassium sulfate and use a small grinder to grind them through an 80-mesh sieve for use. Take 11.00mL of 85% phosphoric acid and add 5mL of water to dilute for use. Weigh 20g of magnesium slag powder passed through a 80-mesh sieve and put it into a beaker, pour the diluted phosphoric acid into the beaker, stir quickly with a glass rod to mix the magnesium slag and phosphoric acid evenly, and then add 41.04g of urea powder passed through an 80-mesh sieve and 27.20g of industrial potassium sulfate powder, mix well and add 8mL of water, mix and granulate in a disc granulator, then put the granules into a small coating machine, add 7g of cement, roll for a certain period of time, and use The constant temperature heater blows and dries the fertilizer. After the drying is completed, the binder (self-made organic binder) is sprayed into the coating machine, and then 8g of cement is added, and it is rotated ...

Embodiment 3

[0034] Weigh a certain amount of magnesium slag, urea, and industrial potassium sulfate and use a small grinder to grind them through an 80-mesh sieve for use, absorb 8.75mL of 85% phosphoric acid and add 5mL of water to dilute for use. Weigh 20g of magnesium slag powder passed through a 80-mesh sieve and put it into a beaker, pour the diluted phosphoric acid into the beaker, stir quickly with a glass rod to mix the magnesium slag and phosphoric acid evenly, and then add 41.04g of urea powder passed through an 80-mesh sieve and industrial potassium sulfate powder 27.20g, mix well, add 8mL water, and granulate in a disc granulator. After granulation, put it into a small coating machine, add 7g of magnesium slag, and after rolling for a certain period of time, use a constant temperature heater to blow dry the fertilizer. After drying, spray a binder (self-made organic binder) into the coating machine, and then Add 8g of magnesium slag, rotate for a certain period of time, and th...

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